The invention which is the subject of this application relates to broadcast data receiver apparatus for the control and provision of power supply to components of a broadcast data receiving system which utilizes a Low Noise Block (LNB) either singly, or in combination, as part of the data receiving apparatus.
Typically, broadcast data receiving apparatus incorporates a means for receiving data which is broadcast from a remote location (the head end) to a number of locations, each equipped with the apparatus. In one system, the data is broadcast via a satellite transmission system whereby the data is received at a number of premises, each equipped with an antenna which includes at least one LNB for the reception of data carried at certain frequencies. When received by the LNB, the data passes to a Broadcast data receiver (BDR) mounted within the premises which is provided with the means to decode and process the data to allow the generation of video, audio and or other services, typically via a television set to which the BDR is connected or may be provided as part of the television set.
At the present time, the BDR is required to be able to supply sufficient power to the LNB or LNB'S to allow the same to be operable. Typically, conventional LNB power supplies with the BDR are required to be able to generate two distinct output voltages, normally 13 volts and 18 volts. However due to power dissipation which occurs, the actual levels which are required to be generated are normally two unregulated power rails of 16 volts and 20 volts respectively.
Indeed at relatively extreme loads such as 400 mA, there can be up to 1.2 Watts of power dissipation in the regulator for the LNB. This is typically dissipated in the form of heat and so it will be appreciated that at the present time the design of power supply which is used means that the unregulated power supply rails need to be sufficiently high in order to guarantee enough power capacity with extreme loads on other power supply rails.